Pump System

ABSTRACT

A pump system includes: a metallic flow path housing including a suction portion configured to suction a fluid and a discharge portion configured to deliver the suctioned fluid; and a resin motor housing configured to drive a pump rotor existing inside the flow path housing in a state of being fitted and connected to the flow path housing, in which the flow path housing includes a first fitting portion having a cylindrical inner circumferential surface, and a first flange portion in an attitude perpendicular to a center axis that becomes a center of the inner circumferential surface, and the motor housing includes a second fitting portion having a columnar outer circumferential surface and a second flange portion, and on an outer circumferential surface of the second fitting portion, protrusions are formed.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is based on and claims priority under 35 U.S.C. § 119to Japanese Patent Application 2016-185301, filed on Sep. 23, 2016, theentire contents of which are incorporated herein by reference.

TECHNICAL FIELD

This disclosure relates to a pump system in which a flow path housing,through which a fluid flows, and a motor housing, which drives a pumprotor inside the flow path housing, are connected to each other.

BACKGROUND DISCUSSION

As an example of a pump system that supplies cooling water to an engineof a vehicle, JP 2008-025538 A (Reference 1) discloses a technique inwhich a flow path housing (referred to as a pump case in Reference 1) isattached to a motor housing (referred to as a motor case in Reference 1)that constitutes a motor unit, and a pump rotor having a plurality ofimpellers is accommodated in the flow path housing.

In Reference 1, a shaft is provided of which one end is supported by themotor housing and the other end supported by the flow path housing, anda rotor unit is rotatably fitted on the shaft. The pump rotor isconfigured by providing a permanent magnet to the rotor unit andproviding a plurality of impellers at the end position of the rotorunit.

In addition, in Reference 1, in view of the drawings thereof, the motorhousing and the flow path housing are connected to each other by makingflange portions formed on the motor housing and the flow path housingabut on each other and fitting the fitting portions formed on the outercircumferences of the flange portions to each other.

In the water pump described in Reference 1, the flow path housing isformed of a resin, and the portion of the motor housing, which is fittedto the flow path housing, is formed of a resin. Even in theconfiguration provided with such fitting structures, it is difficult tomaintain high fitting accuracy since the fitting structures are bothformed of a resin material.

Therefore, in the configuration in which one end of the shaft issupported by the motor housing and the other end is supported by theflow path housing, it is also considered that axial centering accuracymay be deteriorated.

In order to solve the problems, a configuration in which the flow pathhousing and the motor housing are formed of a metal material and arefitted to each other in the same manner as in Reference 1 is effective.However, when considering insulation performance or manufacturing costs,it is required to use a resin material for the motor housing.

Thus, a need exists for a pump system which is not susceptible to thedrawback mentioned above.

SUMMARY

A feature of a pump system according to an aspect of this disclosureresides in that the pump system includes: a metallic flow path housingincluding a suction portion configured to suction a fluid and adischarge portion configured to deliver the suctioned fluid; and a resinmotor housing configured to drive a pump rotor existing inside the flowpath housing in a state of being fitted and connected to the flow pathhousing, in which the flow path housing includes a first fitting portionhaving a cylindrical inner circumferential surface and a first flangeportion in an attitude perpendicular to a center axis that becomes acenter of the inner circumferential surface, the motor housing includesa second fitting portion having a columnar outer circumferential surfacefitted into the first fitting portion and a second flange portionconnected to the first flange portion, and on an outer circumferentialsurface of the second fitting portion, a plurality of protrusions areformed to protrude to a position at which the protrusions have adiameter larger than an inner diameter of the inner circumferentialsurface of the first fitting portion, and the first fitting portion andthe second fitting portion are connected to each other in a state wherea gasket is sandwiched between the first flange portion and the secondflange portion.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and additional features and characteristics of thisdisclosure will become more apparent from the following detaileddescription considered with the reference to the accompanying drawings,wherein:

FIG. 1 is a partially cut-away side view of a pump system;

FIG. 2 is an exploded side view of the pump system, a portion of whichis illustrated in a cross section;

FIG. 3 is a view illustrating the arrangement of a second flangeportion, a second fitting portion, protruding pieces, and so on;

FIG. 4 is a view illustrating the arrangement of a first flange portion,a first fitting portion, and so on;

FIG. 5 is a perspective view illustrating the shapes of a protrudingpiece and a recessed portion; and

FIG. 6 is a cross-sectional view illustrating the state of a protrusionin a state where the first fitting portion and the second fittingportion are fitted to each other.

DETAILED DESCRIPTION

Hereinafter, embodiments disclosed here will be described based on thedrawings.

[Basic Configuration]

As illustrated in FIG. 1, a pump system 100 is configured by fitting andconnecting a metallic flow path housing 10, which is connected to thebottom wall of an engine 1 so as to return, to the engine 1, coolingwater (an example of the fluid) returned from a radiator and so on via ahose 2, and a resin motor housing 20 configured to drive a pump unit Pinside the flow path housing 10 and accommodate an electric motor Mtherein.

In the pump system 100, when the engine 1 is operated, a pump rotor 22of the pump unit P is driven by driving force of the electric motor Maccommodated in the motor housing 20, so that circulation of the coolingwater is implemented in the form of suctioning the cooling water fromthe radiator and so on into the flow path housing 10 and returning thecooling water to a water jacket of the engine 1.

[Flow Path Housing]

As illustrated in FIGS. 1 and 2, the flow path housing 10 includes aflow path housing body 11 in which a flow path space is formed todeliver the cooling water. The flow path housing body 11 is integrallyformed, on the base end side thereof, with a discharge portion 12, whichis connected to the bottom portion of the engine 1, and is provided, onthe outer end side thereof, with a suction portion 13, to which the hose2 is connected.

In the pump system 100, since the pump unit P is formed in a centrifugaltype, a circular pump chamber 11 a centered on the center axis X isformed in the flow path housing body 11, and a discharge flow path 11 bis formed to extend from the outer circumference of the pump chamber 11a toward the discharge portion 12.

A connecting portion 14 is formed in a flange shape on the dischargingportion 12 to connect the flow path housing body 11 to the engine 1.When the connecting portion 14 is connected to the engine 1 byconnecting bolts 3, the discharge flow path 11 b of the dischargeportion 12 communicates with the water jacket of the engine 1.

In addition, the suction portion 13 is formed in a cylindrical shape andfixed to the flow path housing body 11 by fixing bolts 4 in a directionalong the center axis X. As a result, the suction portion 13 and thepump chamber 11 a communicate with each other. In addition, a supportportion 15 is formed coaxially with the center axis X inside the flowpath housing body 11 to support the axial end of a rotor shaft 21 of thepump rotor 22. In addition, the suction portion 13 may be integrallyformed with the flow path housing 10.

In the pump system 100, the rotor shaft 21 is fixedly installed in themotor housing 20, and a motor rotor (not illustrated) and the pump rotor22, which is integrally formed with the motor rotor, are rotatablysupported with respect to the rotor shaft 21. In addition, instead ofthis configuration, the pump system 100 may be configured such that therotor shaft 21 is provided to be driven by the electric motor M and thepump rotor 22 rotates integrally with the rotor shaft 21.

In particular, as illustrated in FIG. 4, the flow path housing body 11includes a first fitting portion 16, which has a cylindrical innercircumferential surface having a circular cross-sectional shape centeredon the center axis X, and a first flange portion 17, which has a firstconnecting surface 17S in the attitude perpendicular to the center axisX of the inner circumferential surface. A plurality of (four in thisembodiment) screw-hole portions 17 a are formed in the first flangeportion 17.

The four screw-hole portions 17 a are formed at positions at which thecircumference centered on the center axis X is equally divided into fourportions (positions at which 360 degrees are divided by 90 degreesaround the center axis X).

In addition, a seal groove 17G, which has a circular shape centered onthe center axis X, is formed in the first connecting surface 17S of thefirst flange portion 17, and an annular gasket 6 formed of a flexiblematerial such as rubber or resin, is fitted therein. The gasket 6 usedhere is sized to slightly protrude from the first connecting surface17S.

[Motor Housing]

As illustrated in FIGS. 1 to 3, the motor housing 20 accommodates theelectric motor M therein, and includes the rotor shaft 21 coaxiallydisposed with the center axis X. The pump rotor 22 is supported by therotor shaft 21, and a plurality of impellers 22 a are formed on the pumprotor 22.

The motor housing 20 is provided with a second fitting portion 23, whichhas a columnar shape centered on the center axis X and has a columnarouter circumferential surface centered on the center axis X so as to befittable into the first fitting portion 16, and a second flange portion24, which has a second connecting surface 24S in the attitudeperpendicular to the center axis X. A plurality of bolt insertion holes24 a (four in this embodiment) are formed in the second flange portion24.

In addition, the four bolt insertion holes 24 a are formed at positionsat which the circumference around the rotor shaft 21 is equally dividedinto four portions so as to correspond to the four screw-hole portions17 a.

As illustrated in FIG. 3, a plurality of (four) protruding pieces 25(e.g., protrusions) each having a thin plate shape are formed on theouter circumferential surface of the second fitting portion 23 onimaginary straight lines that interconnect the center axis X and therespective bolt insertion holes 24 a. The protruding pieces 25 areformed to protrude to a position at which the protruding pieces 25 havea diameter larger than the inner diameter of the inner circumferentialsurface of the first fitting portion 16. That is, the protrudingdistance D to the protruding end of each protruding piece 25 based onthe center axis X is set to a value that is larger than the radius R ofthe inner circumferential surface of the first fitting portion 16, asillustrated in FIG. 4.

As illustrated in FIG. 2, compared with the fitting distance L (fittingmargin) of the second fitting portion 23 in the direction along thecenter axis X, the region length N of the protruding piece 25 from thesecond connecting surface 24S is set to a value that is smaller than thefitting distance L. In addition, as illustrated in FIG. 4, theprotruding distance D to the protruding end of the protruding piece 25based on the center axis X is set to a value that is sufficientlysmaller than the groove radius E to the inner position of the sealgroove 17G, which has a circular shape centered on the center axis X, inthe first connecting surface 17S. In particular, the offset distance Qfrom the first fitting portion 16 to the inner position of the sealgroove 17G is longer than the region length N.

In addition, as illustrated in FIGS. 3 and 5, in the second connectingsurface 24S of the second flange portion 24, a recessed portion 26 isformed in a region surrounding the protruding piece 25 when viewed inthe direction along the center axis X. In particular, since theprotruding piece 25 is integrally formed with the motor housing 20, theprotruding piece 25 is also formed of a resin material.

As illustrated in FIG. 1, in the state where the second fitting portion23 is fitted to the first fitting portion 16 and connected by fasteningbolts 5, the pump unit P is constituted by the pump rotor 22 and thepump chamber 11 a in which the pump rotor 22 is disposed. Details ofthis fitting connection will be described later.

The motor housing 20 includes a connector portion 27 provided on theouter end of the second flange portion 24. In addition, a cover body 28is provided to cover the motor housing 20, and a flange-shapedconnecting body 28 a is integrally formed on the cover body 28 tooverlap the outer surface side of the second flange portion 24. Theconnecting body 28 a has hole portions 28 b formed at positions at whichthe hole portions 28 b overlap the bolt insertion holes 24 a in thesecond flange portion 24.

[Fitting Connection]

When the first fitting portion 16 and the second fitting portion 23 arefitted and connected to each other, the operations of setting the pumprotor 22 in the motor housing 20, disposing the cover body 28 at theposition at which it covers the motor housing 20, and inserting theouter circumferential surface of the second fitting portion 23 into theinner circumferential surface of the first fitting portion 16 areperformed.

During the operations, a fastening operation is performed by insertingthe fastening bolt 5 from the hole portion 28 b of the connecting body28 a through the bolt insertion hole 24 a in the second flange portion24, and screwing the fastening bolt 5 into the screw-hole portion 17 aof the first flange portion 17.

When the fastening operation is performed, the motor housing 20 isdisplaced relative to the first fitting portion 16 in the direction inwhich the second fitting portion 23 is inserted in the direction alongthe center axis X. With this displacement, a portion of the plurality(four) of the protruding pieces 25, which protrudes outward from theopening of the first fitting portion 16, comes into contact with theopening edge of the first fitting portion 16, thereby being scraped and,at the same time, pressed (crushed). Thereby, as illustrated in FIG. 6,the gap between the inner circumferential surface of the first fittingportion 16 and the outer circumferential surface of the second fittingportion 23 is filled with the protruding pieces 25.

In this fastening operation, by equally operating the four fasteningbolts 5, for example, the trouble of causing the rotor shaft 21 to betilted with respect to the center axis X or the trouble of causing therotor shaft 21 to have a positional relationship in which the rotorshaft 21 deviates from the center axis X may be eliminated even in astate where a gap is present between the inner circumferential surfaceof the first fitting portion 16 and the outer circumferential surface ofthe second fitting portion 23. Thus, the axial end of the rotor shaft 21on the protruding side is accurately fitted into the supporting portion15 of the flow path housing 10.

In addition, when the shape of the protruding pieces 25 is changed asdescribed above, the protruding pieces 25 may be partially scraped bythe opening edge of the first fitting portion 16 to form fine resinpieces, and the fine resin pieces may be accommodated in the recessedportions 26. As a result, it is possible to eliminate the trouble ofcausing the fine resin pieces to be sandwiched between the firstconnecting surface 17S and the second connecting surface 24S.

As described above, since the offset distance Q is longer than theregion length N, for example, even if the resin of the protruding pieces25, which are scraped by the opening edge of the first fitting portion16, falls in a long piece state in the direction of the gasket 6 withoutbeing cut, the resin in the long piece state does not come into contactwith the gasket 6 and the sealing property is not impaired since themaximum length of the resin in the long piece state is the region lengthN.

By continuing the fastening operation, the second connecting surface 24Sis brought into the state in which the second connecting surface 24Sabuts on the first connecting surface 17S, and the gasket 6 issandwiched therebetween, thereby implementing the sealed state. Inaddition, the connecting body 28 a of the cover body 28 is pressedagainst the outer surface side of the second flange portion 24 by thefastening operation, so that the cover body 28 covers the motor housing20.

As described above, in the state where the second fitting portion 23 isfitted to the first fitting portion 16, even if a gap is present betweenthe inner circumferential surface of the first fitting portion 16 andthe outer circumferential surface of the second fitting portion 23, thedeformed protruding pieces 25 reliably come into contact with the innercircumferential surface of the first fitting portion 16 so as tomaintain the flow path housing 10 and the motor housing 20 in apredetermined proper positional relationship.

OTHER EMBODIMENTS

This disclosure may adopt other configurations as follows, in additionto the above embodiment (the same reference numerals as those in theembodiment are given to components having functions similar to those inthe embodiment).

(a) The number of the protruding pieces 25 (e.g. protrusions) is set to3 or 4 or more. Although it is ideal that, with the configuration inwhich the above-mentioned number is set, all of the protruding pieces 25are disposed at the positions corresponding to the fastening portions ofthe fastening bolts 5 that connect the first flange portion 17 and thesecond flange portion 24 to each other, some of the protruding pieces 25may be disposed at positions spaced apart from the fastening positions.

(b) The plate thickness of the protruding pieces 25 (e.g. protrusions)may be set to be thicker toward the second connecting surface 24S or theprotrusion amount of the protruding pieces 25 based on the outercircumferential surface of the second fitting portion 23 may be set tobe larger toward the second connecting surface 24S. When the protrudingpieces 25 are formed in this way, it is possible to create a betterfitting state.

This disclosure may be used in a pump system in which a motor housing isconnected to a flow path housing.

A feature of a pump system according to an aspect of this disclosureresides in that the pump system includes: a metallic flow path housingincluding a suction portion configured to suction a fluid and adischarge portion configured to deliver the suctioned fluid; and a resinmotor housing configured to drive a pump rotor existing inside the flowpath housing in a state of being fitted and connected to the flow pathhousing, in which the flow path housing includes a first fitting portionhaving a cylindrical inner circumferential surface and a first flangeportion in an attitude perpendicular to a center axis that becomes acenter of the inner circumferential surface, the motor housing includesa second fitting portion having a columnar outer circumferential surfacefitted into the first fitting portion and a second flange portionconnected to the first flange portion, and on an outer circumferentialsurface of the second fitting portion, a plurality of protrusions areformed to protrude to a position at which the protrusions have adiameter larger than an inner diameter of the inner circumferentialsurface of the first fitting portion, and the first fitting portion andthe second fitting portion are connected to each other in a state wherea gasket is sandwiched between the first flange portion and the secondflange portion.

With this configuration, in a case where an operation of fitting thesecond fitting portion of the motor housing into the first fittingportion of the flow path housing is performed, since the first fittingportion is formed of a metal and the second fitting portion is formed ofa resin, in the plurality of protrusions protruding from the outercircumferential surface of the second fitting portion, a portion thereofthat has a diameter larger than that of the inner circumferentialsurface of the first fitting portion is scraped or crushed, so that theprotrusions are brought into close contact with the innercircumferential surface of the first fitting portion. That is, even if agap is present between the inner circumferential surface of the firstfitting portion and the outer circumferential surface of the secondfitting portion, the gap may be filled with some of the plurality ofprotrusions. As a result, even if the first flange portion and thesecond flange portion are connected to each other in a state where thegasket is sandwiched therebetween, the connection is implemented in astate where rattling is suppressed between the first fitting portion andthe second fitting portion.

Therefore, the pump system is configured in which the motor housing andthe flow path housing are fitted and connected to each other with highaccuracy while the motor housing is formed of a resin material.

In the aspect of this disclosure, the plurality of protrusions may bepressed on an inner surface of the first fitting portion in a statewhere the first fitting portion and the second fitting portion arefitted to each other.

With this configuration, in a state where the first fitting portion andthe second fitting portion are fitted to each other, the plurality ofprotrusions are present in a pressed state between the innercircumferential surface of the first fitting portion and the outercircumferential surface of the second fitting portion. Thus, since thegap is filled with the pressed protrusions, a good connection state isimplemented without rattling.

In the aspect of this disclosure, the second flange portion may have arecessed portion formed in a concave shape in a region of a connectingsurface thereof that surrounds the protrusion when viewed in a directionalong the center axis.

With this configuration, when performing an operation of fitting thesecond fitting portion of the motor housing into the first fittingportion of the flow path housing, even if a portion of the protrusion isscraped by the first fitting portion to form fine resin pieces, theresin pieces are accommodated in the recessed portion, therebysuppressing the trouble of causing the resin pieces to be interposedbetween the abutment surfaces of the first flange portion and the secondflange portion.

In the aspect of this disclosure, the protrusions may be disposed near aplurality of fastening portions in which the first flange portion andthe second flange portion are fastened to each other by a bolt.

With this configuration, when the first flange portion and the secondflange portion are fastened to each other by a plurality of bolts,strong force is applied to the protrusions by fastening force of thebolts, thereby enabling transition to the connection state.

The principles, preferred embodiment and mode of operation of thepresent invention have been described in the foregoing specification.However, the invention which is intended to be protected is not to beconstrued as limited to the particular embodiments disclosed. Further,the embodiments described herein are to be regarded as illustrativerather than restrictive. Variations and changes may be made by others,and equivalents employed, without departing from the spirit of thepresent invention. Accordingly, it is expressly intended that all suchvariations, changes and equivalents which fall within the spirit andscope of the present invention as defined in the claims, be embracedthereby.

What is claimed is:
 1. A pump system comprising: a metallic flow pathhousing including a suction portion configured to suction a fluid and adischarge portion configured to deliver the suctioned fluid; and a resinmotor housing configured to drive a pump rotor existing inside the flowpath housing in a state of being fitted and connected to the flow pathhousing, wherein the flow path housing includes a first fitting portionhaving a cylindrical inner circumferential surface, and a first flangeportion in an attitude perpendicular to a center axis that becomes acenter of the inner circumferential surface, the motor housing includesa second fitting portion having a columnar outer circumferential surfacefitted into the first fitting portion and a second flange portionconnected to the first flange portion, and on an outer circumferentialsurface of the second fitting portion, a plurality of protrusions areformed to protrude to a position at which the protrusions have adiameter larger than an inner diameter of the inner circumferentialsurface of the first fitting portion, and the first fitting portion andthe second fitting portion are connected to each other in a state wherea gasket is sandwiched between the first flange portion and the secondflange portion.
 2. The pump system according to claim 1, wherein theplurality of protrusions are pressed on an inner surface of the firstfitting portion in a state where the first fitting portion and thesecond fitting portion are fitted to each other.
 3. The pump systemaccording to claim 1, wherein the second flange portion has a recessedportion formed in a concave shape in a region of a connecting surfacethereof that surrounds the protrusion when viewed in a direction alongthe center axis.
 4. The pump system according to claim 1, wherein theprotrusions are disposed near a plurality of fastening portions in whichthe first flange portion and the second flange portion are fastened toeach other by a bolt.
 5. A pump system comprising: a metallic flow pathhousing including a suction portion configured to suction a fluid and adischarge portion configured to deliver the suctioned fluid; and a resinmotor housing configured to drive a pump rotor existing inside the flowpath housing in a state of being fitted and connected to the flow pathhousing, wherein the flow path housing includes a first fitting portionhaving a cylindrical inner circumferential surface, and a first flangeportion in an attitude perpendicular to a center axis that becomes acenter of the inner circumferential surface, the motor housing includesa second fitting portion having a columnar outer circumferential surfacefitted into the first fitting portion and a second flange portionconnected to the first flange portion, and on an outer circumferentialsurface of the second fitting portion, a plurality of protrusions areformed to protrude to a position at which the protrusions have adiameter larger than an inner diameter of the inner circumferentialsurface of the first fitting portion, the first fitting portion and thesecond fitting portion are connected to each other in a state where agasket is sandwiched between the first flange portion and the secondflange portion, the plurality of protrusions are pressed on an innersurface of the first fitting portion in a state where the first fittingportion and the second fitting portion are fitted to each other, and thesecond flange portion has a recessed portion formed in a concave shapein a region of a connecting surface thereof that surrounds theprotrusion when viewed in a direction along the center axis.
 6. A pumpsystem comprising: a metallic flow path housing including a suctionportion configured to suction a fluid and a discharge portion configuredto deliver the suctioned fluid; and a resin motor housing configured todrive a pump rotor existing inside the flow path housing in a state ofbeing fitted and connected to the flow path housing, wherein the flowpath housing includes a first fitting portion having a cylindrical innercircumferential surface, and a first flange portion in an attitudeperpendicular to a center axis that becomes a center of the innercircumferential surface, the motor housing includes a second fittingportion having a columnar outer circumferential surface fitted into thefirst fitting portion and a second flange portion connected to the firstflange portion, and on an outer circumferential surface of the secondfitting portion, a plurality of protrusions are formed to protrude to aposition at which the protrusions have a diameter larger than an innerdiameter of the inner circumferential surface of the first fittingportion, the first fitting portion and the second fitting portion areconnected to each other in a state where a gasket is sandwiched betweenthe first flange portion and the second flange portion, the plurality ofprotrusions are pressed on an inner surface of the first fitting portionin a state where the first fitting portion and the second fittingportion are fitted to each other, the second flange portion has arecessed portion formed in a concave shape in a region of a connectingsurface thereof that surrounds the protrusion when viewed in a directionalong the center axis, and the protrusions are disposed near a pluralityof fastening portions in which the first flange portion and the secondflange portion are fastened to each other by a bolt.